Rayleigh-Taylor instability of a plasma in a magnetic field: nonlinear theory

Kaira & Kathuria used the method of multiple scales to develop nonlinear analysis of Rayleigh-Taylor instability of a plasma in a magnetic field. Their calculations remain valid only for wavenumbers k away from the linear cut-off value k_c, and break down for wavenumbers near k_c. The purpose of this paper is to treat the latter case. The solution uses the method of strained parameters. The results show the instability persists even at k = k_c, despite the cut-off predicted by the linear theory.